Stud for installation in a panel

ABSTRACT

A stud for installation in a host panel and for fastening a component to the host panel includes at least one shaft having a longitudinal axis. An annular flange extends radially from the shaft at a substantially right angle with respect to the longitudinal axis. A shoulder for engagement with the host panel has a top adjacent to the shaft and a base adjacent to the flange. The shoulder extends radially from the shaft wherein the shoulder and the flange define an undercut therebetween at the base of the shoulder such that a diameter of the shoulder is smaller at the base than at the top. At least one anti-rotation tab is located intermediate between the shoulder top and the flange, and is aligned for engagement with the host panel.

TECHNICAL FIELD

[0001] The invention relates to a fastener. The invention isspecifically related to a self-attaching double or single ended stud.

BACKGROUND OF INVENTION

[0002] Studs are used by the automotive industry to assemble vehicles inwhich many components of various kinds are attached to metal plates orpanels. For example studs are used to attach lamps, brackets, modules,and sheet metal parts to the vehicle. When such parts are attached a nutis placed over the end of the installed stud and the nut is tightenedwith rotating tools such as an air or electric torque gun, set to thespecified torque values. The self-attaching stud must therefore have thenecessary and sufficient anti-torque or rotation resistance (the forcethat keeps the stud from rotating on the mating metal plate when the nutis tightened on the stud).

[0003] When self-attaching studs are being driven into a metal panel thestuds may be continuously supplied to the installation tooling throughan outlet of a supply device, such as a hopper. Studs are easily adaptedto automatic feeding machines because of the large length to diameterratio. The larger the ratio the more efficient the high-speed feedingoperations become.

[0004] After a component is attached to the stud on the metal plate,external forces such as vibration and shear and tensile forces areapplied to the joint (the stud and nut combination with the attachedpart). These forces act upon the stud from the pull through directionattempting to pull the studs from the metal plate in which they areattached. Therefore, the installed stud must have sufficient push outand pull out resistance. Previously, the only way to ensure a very highpush out or pull out force was to weld the stud to the mating material.Earlier attempts to use double-ended studs that were not welded resultedin studs with very low push-in and push-out values. A low push-out valuelimits the number of applications in which the stud can be used, since astud with a low push-out value can not attach parts of any significantamount of mass.

[0005] Thus, there is a need in the industry for a stud that can beattached by means other than welding where the stud also has a very highpush-out force, and where the stud can be configured as either asingle-ended stud or a double-ended stud.

SUMMARY OF THE INVENTION

[0006] One aspect of the present invention is a stud for installation ina host panel and for fastening a component to the host panel, whichincludes at least one shaft, having a longitudinal axis. An annularflange extends radially from the shaft at a substantially right anglewith respect to the longitudinal axis. A shoulder for engagement withthe host panel has a top adjacent to the shaft and a base adjacent tothe flange. The shoulder extends radially from the shaft wherein theshoulder and the flange define an undercut therebetween at the base ofthe shoulder such that a diameter of the shoulder is smaller at the basethan at the top. At least one anti-rotation tab is located intermediatebetween the shoulder top and the flange, and is aligned for engagementwith the host panel.

[0007] Another aspect of the present invention is a double-ended studfor installation in a host panel and for fastening a component to thehost panel wherein the double-ended stud includes a shaft having alongitudinal axis and a first and a second end. An annular flangecoaxial to the shaft is positioned intermediate between the first andsecond ends of the shaft. A shoulder is positioned adjacent to a surfaceof the flange and is coaxial thereto wherein the shoulder has an outerperipheral face. The peripheral shoulder face and the flange surfacedefine an acute angle therebetween. At least one anti-rotation tabextends from one of either the flange surface or the shoulder's outerperipheral face.

[0008] Yet another aspect of the present invention is a method forinstalling a double-ended stud in a host panel aperture wherein the studhas an annular flange with anti-rotation tabs and further includes ashoulder with a crown and a face with a back angled portion. The methodfor installation comprises the steps of supporting one end of the studand the stud flange with an installation fixture and then placing aninstallation punch over the opposite end of the stud wherein theinstallation punch has a face portion bearing on the shoulder crown andan annular protrusion bearing on the panel area proximate to the panelaperture receiving the stud. Next, a force is applied by the punch in adirection toward the installation fixture and deforming the panelmaterial around the anti-rotation tabs. The applying force furthercausing the flowing of panel material that defines the panel apertureinto the back angled portion of the shoulder and deflecting the shouldercrown radially outward to engage the panel at the periphery of the panelaperture.

[0009] These and other advantages of the invention will be furtherunderstood and appreciated by those skilled in the art by reference tothe following written specification, claims and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a perspective view of a double-ended stud embodying thepresent invention.

[0011]FIG. 2 is an elevational view of a stud at the beginning of thefinal step of the stud forming process with the header tool (in section)partially advanced and beginning to form the back angled portion of theshoulder.

[0012]FIG. 3 is an elevational view of a stud at the final step of thestud forming process with the header tool (in section) fully advancedand the back angled shoulder fully formed.

[0013]FIG. 4, is an elevational view of a stud and installation punch inpartial cross-section showing the finished stud inserted in a matingmetal panel with the installation punch ready to deform the mating panelinto the back angled portion of the stud.

[0014]FIG. 5 is an elevational view of the stud and installation punchin partial cross-section showing the punch having deformed the matingmetal panel into the back angled portion of the stud.

[0015]FIG. 6, is an elevational view in partial cross-section of a studinstalled in a mating panel illustrating the flow of panel metal intothe back angled portion of the stud and into engagement with theanti-rotation feature of the stud.

[0016]FIG. 7 is a perspective view of an alternate embodiment of thestud wherein the back angled shoulder of the stud comprises amulti-sided polygon.

[0017]FIG. 8 shows an alternate embodiment of a single endedself-attaching stud.

[0018]FIG. 9 shows an elevation view of an installed stud similar toFIG. 5 wherein the installation punch deforms the host panel to be flushwith the flange bottom.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] For purposes of description herein, the terms “upper”, “lower”,right”, “left”, “rear”, “front”, “vertical”, “horizontal”, andderivatives thereof shall relate to the invention as oriented in FIGS. 1and 2. However, it is to be understood that the invention may assumevarious alternative orientations and step sequences, except whereexpressly specified to the contrary. It is also to be understood thatthe specific devices and processes illustrated in the attached drawings,and described in the following specification are simply exemplaryembodiments of the inventive concept defined in the appended claims.Hence, specific dimensions and other physical characteristics relatingto the embodiments disclosed herein are not to be considered aslimiting, unless the claims expressly state otherwise.

[0020] Turning to the drawings, FIG. 1 shows a double-ended stud 10,which is one of the preferred embodiments of the present invention, andillustrates its various components.

[0021] Stud 10 in its preferred embodiment comprises a threaded uppershaft 12 and a co-axial lower threaded shaft 14. An annular flange 16 ispositioned between shafts 12 and 14 and extends radially therefrom at asubstantially right angle to the longitudinal axis of shafts 12 and 14.A shoulder 24 is adjacent the upper surface 18 of flange 16. Shoulder 24extends radially from upper threaded shaft 12 wherein a top portion ofthe shoulder has a recess 26 immediately adjacent shaft 12 and a crownportion 28 at its outer periphery. The base of shoulder 24 is adjacentto the upper surface 18 of flange 16. Face 34 of shoulder 24 and uppersurface 18 of flange 16 define an undercut 30 such that the diameter ofshoulder 24 is smaller at its base than at the top or crown portion 28.At least one anti-rotation tab 22 protrudes into the area between crownportion 28 and upper surface 18 of flange 16.

[0022] The self-attaching portion of the stud 10, comprising shoulder24, anti-rotation tabs 22, and flange 16 is formed in a multi-stepprocess. Typically, there are three to five steps or stations, morecommonly called “blows” required in the heading process to fully formthe attaching portion of the stud. The initial steps in the headingprocess are well known in the art and, while described herein, are notshown in the figures. Initially, coiled wire is fed into the headingmachine and the wire is cut to the required length in and positioned inthe first die. The die then begins to form annular flange 16, andshoulder 24 above annular flange 16. The shoulder 24 may be formed in avariety of shapes such as circular, square, octagonal, or any otherpolygonal shape with the preferred embodiment being a circular shoulder24 as shown in FIG. 1. In the later stages of the heading operationanti-rotation tabs 22 are partially formed on the top 18 of the annularflange 16. Anti-rotation tabs 22 can be formed as any geometricirregularity to prevent stud 10 from rotating in its host panel afterinstallation described below. Each successive step or blow to the studin the header moves progressively more metal towards the final shape ofthe stud.

[0023] FIGS. 2-3 illustrate the last station of the header processwherein a back angle between shoulder face 34 and top surface 18 offlange 16 is formed defining back angled portion 30 of the stud 10. Inthis operation the die 46 in the header tool has an aperture 48 intowhich is received upper shaft 12 of stud 10. Die 46 contains an annularnose 52 on the surface of the tool about the periphery of aperture 48.As the header tool advances it forces the annular nose 52 on the die tomake contact with the top of shoulder 24 of the stud 10. The advancementof the tool creates pressure that is applied to the top 28 of theshoulder 24 and forces the top or crown 28 of the shoulder 24 radiallyoutward from the center of the stud and also creates recessed portion26. This forms the back angled portion 30 between the top surface 18 ofthe annular flange 16 and the top 28 of the shoulder 24.

[0024] The height of shoulder 24 required for a particular applicationdepends on the thickness of material into which it is to be installed.The height dimension from upper surface 18 of flange 16 to crown 28 isslightly greater than the material thickness into which it is to beinstalled. Those skilled in the art will readily recognize that sincethere are specific standard gages of sheet material used in industryonly a limited number of shoulder sizes need be produced to accommodatethese standard gages.

[0025] Referring now to FIGS. 4-6, a stud 10 according to the preferredembodiment is shown for installation in mating panel 76. As illustratedin FIG. 4, flange 16 of stud 10 rests on an upper surface 64 ofinstallation fixture 60 such that lower threaded shaft 14 extends intoor is received by aperture 62. Mating panel 76 rests on top ofanti-rotation tabs 22 on the upper surface 18 of flange 16. It will alsobe noted that the crown portion 28 of shoulder 24 extends above an uppersurface of mating panel 76. An installation punch 66 having an aperture67 therethrough is lowered over stud 10 such that upper threaded shaft12 is received into aperture 67. The bottom portion of installationpunch 66 has an inner bottom surface 70 immediately adjacent theperiphery of aperture 67 and also has an annular protrusion 68 extendingbelow inner bottom surface 70. The arrangement of crown 28, the uppersurface of mating panel 76, inner bottom surface 70, and annularprotrusion 68 is such that annular protrusion 68 contacts the uppersurface of mating panel 76 substantially coincident with the contact ofinner bottom surface 70 with crown 28. Those skilled in the art willunderstand that slight variations in this arrangement are possible whilemaintaining the intent and scope of the invention. Those skilled in theart will also understand that the size of the hole and mating panel 76that receives the shoulder 24 of stud 10 is marginally greater than thelargest diameter of shoulder 24. In such a manner, there is a relativelylarger clearance between the aperture wall and shoulder 24 in the areaof undercut 30 while maintaining a relatively minimum clearance betweenthe aperture wall and the upper portion of shoulder 24 more proximate tocrown 28.

[0026] Turning now to FIG. 5, the mating of stud 10 to mating panel 76is complete wherein the installation punch has been forced towardinstallation fixture 60 with sufficient pressure that the material ofmating panel 76 has flowed to contour over anti-rotation tabs 22 andcome in contact with upper surface 18 of flange 16. Additionally,annular protrusion 68 by deformably bearing into the upper surface ofmating panel 76 has caused the material about the periphery of shoulder24 to flow into back angled area 30 and conform to the contour ofshoulder face 34. Additionally, inner bottom surface 70 of installationpunch 66 bearing against crown 28 has displaced crown 28 downward andradially outward to further engage mating panel 76.

[0027] Upon completion of the operation shown in FIG. 5, the mated panel76 and stud 10 can be removed from the installation fixture 60 andinstallation punch 66. The final stud as installed is shown in FIG. 6 inpartial cross-section showing the anti-rotation tab 22 extending into orabove the bottom surface of mating panel 76. A recess 78 created byannular protrusion 68 is apparent in the top surface of mating panel 76proximate to and about the periphery of crown 28. Additionally, themating panel 76 material about the periphery of shoulder 24 has flowedinto contact with shoulder face 34 and into back angled area 30 thusfirmly affixing stud 10 in mating panel 76.

[0028] The flowing of the peripheral material of panel 76 into theundercut or back angled area 30 of panel 24 and also as a result of theexpansion of crown 28 into interfering contact with the material ofmating panel 76, the self-attaching stud can accommodate a very highpush out force. Those skilled in the art will understand that byadjusting the angle, height, or diameter of shoulder 24 and thus thebearing area of shoulder face 34, the push out force of the combinedpanel and stud can be adjusted to meet the needs for a particularapplication.

[0029] Turning now to FIG. 7, an alternate embodiment stud 80 is shownhaving an upper non-threaded shaft 81 and a lower threaded shaft 82,thereby illustrating that the upper shaft 81 and lower shaft 82 can beconfigured differently depending on the requirements for a particularinstallation. Further, shoulder 83 is shown as a multi-sided elementhaving a plurality of sides forming a periphery of the shoulder. In theillustrated embodiment, the shoulder is shown as an octagon, however,any multiple sided polygon can be utilized. Those skilled in the artwill also readily recognize that the intersection of adjacent sides ofthe polygon forming shoulder 83 can also function as anti-rotation tabsand therefore eliminate the necessity to form anti-rotation tabs on theupper surface of flange 88. Stud 80 also includes a back angled area 87and a crown area 85 to shoulder 83 wherein back angled area 87 and crown85 are formed in a manner similar to stud 10 whereby a header tool die46 having a nose 52 is pressed down upon a top surface of shoulder 83.

[0030]FIG. 8 shows yet another embodiment wherein stud 90 is a singleended stud having one threaded shaft 91 extending upwardly from flange94 and shoulder 92. Shoulder 92 and anti-rotation tabs 93 are identicalto shoulder 24 and anti-rotation tab s 22 as shown in stud 10 above.Stud 90 is shown to illustrate that the lower shaft can be eliminatedwhile still incorporating the features of the instant invention on asingle ended stud.

[0031]FIG. 9 illustrates an alternate punch 73 for installing stud 10 inpanel 76. Punch 73 mates panel 76 to the shoulder 24 of the stud 10 in amanner identical to that of punch 66. However, punch 73 also includes anouter annular area 74 that extends downwardly from the outer peripheryof punch 73. As inner bottom surface 70 and annular protrusion 68forgingly mate shoulder 24 and panel 76, outer annular area 74 deformspanel 76 downwardly around flange 16 so that the bottom surface offlange 16 and the bottom surface of panel 76 are substantially flush.

[0032] In the foregoing description, those skilled in the art willreadily appreciate that modifications may be made to the inventionwithout departing from the concepts disclosed herein. Such modificationsare to be considered as included in the following claims, unless theseclaims expressly state otherwise.

1. A stud for installation in a host panel and for fastening a componentto the host panel, said stud comprising: at least one shaft having alongitudinal axis; an annular flange extending radially from said shaftat a substantially right angle with respect to said longitudinal axis; ashoulder for engagement with the host panel, said shoulder having a topadjacent said shaft and a base adjacent to said flange, said shoulderextending radially from said shaft, said shoulder and said flangedefining an undercut therebetween at said base such that a diameter ofsaid shoulder is smaller at said base than at said top; and at least oneanti-rotation tab intermediate said shoulder top and said flange, saidat least one anti-rotation tab aligned for engagement with said hostpanel.
 2. The stud according to claim 1 wherein said shoulder has acircular perimeter.
 3. The stud according to claim 1 wherein saidshoulder has a plurality of sides defining a polygonal perimeter.
 4. Thestud according to claim 3 wherein said at least one anti-rotation tab isa corner defined by two adjacent sides of said polygonal perimeter. 5.The stud according to claim 1 wherein said shoulder includes adeformable crown at an outer periphery of said top, said crown defininga recess at an inner periphery of said top adjacent to said at least oneshaft.
 6. The stud according to claim 1 wherein said at least oneanti-rotation tab extends from an upper surface of said annular flange.7. The stud according to claim 1 wherein said at least one anti-rotationtab extends from a face of said shoulder
 8. A double ended stud forinstallation in a host panel and for fastening a component to the hostpanel, said double ended stud comprising: a shaft having a longitudinalaxis, first end and a second end; an annular flange co-axial to saidshaft and positioned intermediate said first and said second ends; ashoulder adjacent to a surface of said flange and coaxial thereto, saidshoulder having an outer peripheral face, said peripheral shoulder faceand said flange surface defining an acute angle therebetween; and atleast one anti-rotation tab extending from one of said flange surface orsaid shoulder outer peripheral face for engaging the host panel.
 9. Thestud according to claim 8 wherein said shoulder face has a cylindricalperimeter.
 10. The stud according to claim 8 wherein said shoulder facecomprises a plurality of sides defining a polygonal perimeter.
 11. Thestud according to claim 10 wherein said at least one anti-rotation tabis a corner defined by two adjacent sides of said polygonal perimeter.12. The stud according to claim 8 wherein said shoulder includes adeformable crown at an outer periphery at a top of said shoulder, saidcrown defining a recess at an inner periphery of said top adjacent tosaid shaft.
 13. The stud according to claim 8 wherein said at least oneanti-rotation tab protrudes from an upper surface of said annularflange.
 14. The stud according to claim 8 wherein said at least oneanti-rotation tab protrudes from said face of said shoulder.
 15. Amethod for installing a double ended stud in a host panel aperturewherein the stud has an annular flange with anti-rotation tabs andfurther has a shoulder with a crown and a face with a back angledportion, said method comprising the steps: supporting one end of thestud and the stud flange with an installation fixture; placing aninstallation punch over an opposite end of the stud wherein theinstallation punch has a face portion bearing on the shoulder crown andan annular protrusion bearing on the panel area proximate to the panelaperture receiving the stud; applying force to the punch in a directiontoward the installation fixture; deforming the panel material around theanti-rotation tabs; flowing the panel material defining the panelaperture into the back angled portion; and deflecting the shoulder crownradially outward to engage the panel at the periphery of the panelaperture.
 16. The method according to claim 15, wherein the stud to beinstalled does not have a back angled portion and the applying forcestep includes forming a back angled portion at a base of the shoulder.